International Journal of Engineering & Technology Sciences (IJETS) Vol. (issue): pages, yearISSN xxxx-xxxx© Academic Research Online Publisher

Research Article

Title

Authur a,b, author c,*, author b,d, author e

a Department of Mechanical Engineering, Universiti Teknologi PETRONAS, Perak, Malaysiab Kish University, Kish Island, Iranc School of Materials and Mineral Resources Engineering, Universiti Sains Malaysia, Malaysiad Department of Materials Engineering, Sharif University of Technology, Tehran, Irane Nano-Optoelectronic Research (NOR) Lab, School of Physics, Universiti Sains Malaysia, Malaysia

* Corresponding author. Tel.: ……….; fax: ……………..E-mail address:……………….

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A b s t r a c tOne effective method for preventing corrosion of steel reinforcement and improving the mechanical properties of concrete is changing the physical nature of concrete by adding different materials. In this study, we have used polypropylene fibers as an additional material. We have compared the corrosion rate of rebar using different volume ratios and sizes of polypropylene fibers. Reinforcement potential increased as the amount of fibers increased from 0 to 2 kg m_3. The polypropylene fibers delay the initial corrosion process by preventing cracking, thereby decreasing permeability of the concrete. In addition, the corrosion rate of concrete samples made with Kish Island coral aggregate was compared to samples made with a siliceous aggregate. The corrosion rate in this concrete is more than twice that in siliceous concrete. We concluded that coral aggregate is improper for making concrete and using in concrete structures in the onshore atmosphere.

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Keywords:CorrosionPermeabilityFibers reinforced concretePolypropylene

1. Introduction

It is generally understood that the initially protective environment that concrete provides for steel is

due to the alkaline nature of concrete. This is usually reflected in passive or nobler corrosion

potentials (or Ecorr values) for steel in concrete. When aggressive ions such as chlorides penetrate

into concrete, the environment can become favorable for steel corrosion [1, 2].

2. Experimental procedures

2.1. Materials and mix design

An ordinary Portland cement, equivalent to ASTM type II, was used to prepare the mortar specimens.

Siliceous sand ranging between 0 and 6 mm diameter and tap water were employed at laboratory

temperature (20–25 °C). Cylindrical reinforced concrete specimens 10 cm in diameter and 20 cm in

height were used. The composition of the concrete is given in Table 1. As shown in Fig. 1, an air–

Author et al. / International Journal of Engineering & Technology Sciences (IJETS) Vol. (issue): pages, year

tape–concrete–steel interface and electroplater’s tape were used for minimizing crevice corrosion. The

main physical characteristics of the polypropylene fibers are listed in Table 2. In this research,

concrete samples were prepared with volumetric ratios of fibers: 0, 0.5, 1, 1.5 and 2 kg.m -3 as

mentioned in our previous work [19]. Usable aggregate must be in the special range for suitable

mixing design and least permeability. Aggregate size was selected similar to ASTM C33 [20].

2.2. Experimental test

A triple-electrode system was used for electrochemical measurements. The electrode consisted of a

reinforced concrete specimen as the working electrode. A saturated calomel electrode (SCE) and a

platinum electrode were used as reference and counter, respectively. An EG&G Model ZAHNER IM6

potentiostat, was used for electrochemical measurements. In addition, a computer program was used

with a scan rate of 1 mV/s in order to analyze the resistance to polarization. The variations of

corrosion potential (Ecorr) with time were recorded with respect to a saturated calomel reference

electrode at room temperature.

Table.2: Physical characteristics of polypropylene fibers.

3. Results and discussion

Author et al. / International Journal of Engineering & Technology Sciences (IJETS) Vol. (issue): pages, year

Fig. 1. Polarization curves of concrete samples with different volumetric amount of polypropylene fibers after 150 days exposure in sea water. Numbers (1–5) indicate volumetric amount of polypropylene fiber as follows: 1

= 0.5 kg.m-3, 2 = 1 kg. m-3, 3 = 1.5 kg. m-3, 4 = 2 kg.m-3, and 5= 0 kg.m-3 polypropylene fibers.

4. Conclusions

The following conclusions can be drawn from this research:

i. Polarization curves became more positive with increasing volumetric ratio of polypropylene fibers.

ii. Samples with fiber volumetric ratios of 1.5 kg.m-3 indicated better corrosion resistance compared to

the other samples.

iii. In this research, using coral aggregate for producing concrete samples showed that this concrete

composition was not a practical composition. Corrosion rate in this concrete was at least twice that

was shown in siliceous concrete.

iv. The results show that 6 mm length fibers were not the suitable size to be used in concrete. The

result of using fibers with length of 12 and 19 mm was approximately the same, with the optimum

size being 12 mm.

v. Apart from increasing corrosion resistance, the presence of polypropylene fibers decreased the

permeability, volumetric expansion and contraction of concrete, which in turn had reduced the chance

of concrete cracking.

Author et al. / International Journal of Engineering & Technology Sciences (IJETS) Vol. (issue): pages, year

Acknowledgments

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